What does your birth order say about you, if anything at all?

Eldest daughter syndrome, middle child personality, youngest child behavior… Does your position in the sibling lineup actually influence who you are? Not really, say experts. Despite how historically prevalent, and sometimes accurate, these categories are, more recent studies found no correlation between birth order and personality.

Where did this idea come from? Alfred Adler, largely heralded as the father of individual psychology, came up with the theory that a person’s “family constellation” manifested in predictable personality characteristics.

Yet older studies have found a surprising amount of associations between birth order and personal choices. Frank Sulloway, an American psychologist and one of the biggest contemporary proponents of the theory, studied the careers of people in the 1900s and 2000s and found that firstborn professionals were more conservative in their approach to work, while those lower in the family tree tended to be more radical. The opposite was true for those in the political sphere.

So why is this theory being disregarded now? The main markers of personality development look at openness, conscientiousness, extroversion, agreeableness, and neuroticism. More recent studies show no correlation between those personality traits and birth order. In fact, Rodica Damian, a psychology professor who conducted one of the largest studies using 440k students, says that “the association between birth order and personality traits is as close to zero as you can get.”

But… Both Damian and another team of researchers found that firstborn children showed slightly higher verbal intelligence than their younger siblings. Before you go texting the family group chat to boast, this is likely due to firstborns being around adults more during their early childhood than their younger siblings, and has no impact on intelligence or learning skills.

So what makes up a personality? We’re not completely sure yet. Current research indicates that 40% of what makes us who we are is due to biologically inherited traits. The rest is up for grabs, but environment and cultural practices are key players.